Metal working lubricant

ABSTRACT

A metal working lubricant which can be used for drawing and ironing of sheet stock as well as used as a mechanical lubricant such as a hydraulic oil in the associated metal working equipment comprises a combination of a carboxylic acid; a film forming and wetting agent which comprises a long chain mono or diester of a carboxylic acid; a non-ionic, non-metallic ester or ether emulsifier; and a mineral oil. The viscosity of the lubricant should be at least 250 Saybolt seconds (SSU) and the lubricant, when emulsified, should preferably have an acidic pH.

[ Dec. 2, 1975 [75] lnventor:

METAL WORKING LUBRICANT James E. Knepp, Pittsburgh, Pa.

[73] Assignee: Aluminum Company of America, Pittsburgh, Pa.

221 Filed: on. 3, 1974 211 Appl. No.: 511,776

[52] US. Cl 252/49.S; 72/42; 252/56 R; 252/56 S; 252/79 [51] Int. Cl.?..Cl0M 1/06; ClOM 3/04;C1OM 5/04;

3,776,848 12/1973 Hall et a1. 252/49.5 3,857,865 12/1974 Sturwold et a1. 252/56 S Primary Exarriiner-Delbert E. Gantz Assistant Examiner-4. Vaughn Attorney, Agent, or Firm-.1ohn P. Taylor, Esq.

[57] ABSTRACT A metal working lubricant which can be used for drawing and ironing of sheet stock as well as used as a mechanical lubricant such as a hydraulic oil in the associated metal working equipment comprises a combination of a carboxylic acid; a film forming and wetting agent which comprises a long chain mono or diester of a carboxylic acid; a non-ionic, non-metallic ester or ether emulsifier; and a mineral oil. The viscosity of the lubricant should be at least 250 Saybolt seconds (SSU) and the lubricant, when emulsified, should preferably have an acidic pH.

8 Claims, 1 Drawing Figure U.S. Patent Dec. 2, 1975 3,923,671

2-8 PARTS |o-2o PARTS BALANCE 4-|o PARTS CARBOXYLIC CARBOXYLIC MINERAL ACID ACID ESTER EMULS'F'ER on.

ifiihr WATER 250-450 ssu VISCOSITY ACIDIC pH AQUEOUS LUBRICANT DISPERSION METAL WORKING LUBRICANT BACKGROUND OF THE INVENTION This invention relates to metal working lubricants and more particularly to a metal working lubricant which can be used in drawing and ironing type fabrication of sheet metal stock.

In the fabricating of metal into complex shapes such as, for example, the drawing and ironing steps used in producing a formed container or can from a sheet of, for example, aluminum or steel, a number of different lubricants are usually involved. Residual oils are present on most sheet surfaces from prior rolling and fabricating operations; an additional process lubricant is used for the drawing operation; a third process lubricant is used for the ironing operation; and yet another lubricant, namely the mechanical or hydraulic lubricant associated with the presss equipment, may, at least in part, become inadvertently mixed with the process lubricants. Normally these lubricants are of different constituency although it is known to use the same lubricant in both drawing and ironing operations although at different concentrations.

It is known to mix carboxylic acids such as fatty acids with mineral oils to produce lubricants. For example, both Moser US. Pat. No. 2,124,628 and Montgomery US. Pat. No. 2,151,353 disclose the use of oleic acid with a mineral oil as a lubricant. However, such lubricants were usually used as neat oils in the 1930s, that is, were not further diluted by dispersion or emulsification in an aqueous medium as is a common practice today.

It is also known to disperse fatty acid esters and soaps in mineral oil lubricants. However, such lubricants are difficult to work with in that filters used to filter out impurities and foreign material (such as metal shavings or the like) are blinded by the soaps. Furthermore, such lubricants having soaps therein are usually somewhat alkaline (pH of about 8 or 9) and subsequent treatment of the formed metal piece with acid cleaners to remove the lubricant therefrom tends to break down the soap and thus the lubricant cannot be recycled or reused.

It has also been found with many prior art lubricants that the residual oils already contained on the metal stock are not compatible therewithwhich further provides a contamination type of effect. The same is true of the hydraulic and mechanical oils used in the presses which, when inevitably some mixture occurs, provide a contamination of the lubricant therefore making it unreusable without reprocessing.

Sawyer U.S. Pat. No. 3,657,126, assigned to the assignee of this invention, describes an emulsifiable lubricant which comprises the combination of a dispersion of an aliphatic carboxylic acid glycol ester in mineral oil with an emulsifying agent to provide emulsification or dispersion of the neat oil in an aqueous media. While this lubricant has been effective in some metal working operations, it has been found that many of the problems enumerated above still exist with the use of this oil for drawing and ironing lubrication.

It is therefore an object of this invention to provide a lubricant dispersible or emulsifiable in water which can be used at some established concentration as both a drawing and ironing lubricant, which can also be used (as a neat oil) as the hydraulic and/or mechanical oil, and which will be compatible with the residual oils usually contained on the metal stock as a result of prior fabricating operations. It is a further object of the invention to provide a lubricant which will be chemically stable in the presence of further acid cleaning treatment to remove the oils from the metal to thereby permit recycling of the lubricant without loss due to contact with acid. These and objects of the invention will be apparent from the description and accompanying flowsheet.

DESCRIPTION OF THE DRAWING The sole DRAWING of the invention is a flowsheet illustrating the components of the lubricant of the invention.

DETAILED DESCRIPTION OF THE DEFERRED EMBODIMENTS This invention provides a water base lubricant comprising a carboxylic acid, an aliphatic carboxylic acid glycol ester, an emulsification agent, and a mineral oil. These ingredients are further dispersed in an aqueous media comprising deionized water or soft water containing less than about 250 ppm hardness. Preferably the amount of the ingredients which will be referred to hereinafter as the neat oil comprise from 4 to 30 parts per 100 parts of the neat oil water dispersion. For purposes of this description, the terms emulsion and dispersion will be considered to be the same.

In accordance with the invention, the neat oil ingredients, in parts by weight, comprise about 2 to 8 parts carboxylic acid, 4 to 10 parts emulsifier, and 10 to 20 parts of the aliphatic carboxylic acid ester, with the balance made up of mineral oil for a total of 100 parts. The viscosity of the total mixture of neat oil should be at least about 250 to 450 Saybolt Seconds Universal (SSU) at 100F, although a somewhat higher viscosity such as 500-550 SSU (at 100F) can be used when operating at higher process equipment temperature. Depending upon the amount of the ingredients other than the mineral oil and their effect on viscosity, the viscosity of the mineral oil will be selected to provide this finalviscosity of the blend.

In accordance with the invention, the carboxylic acid useful in the invention must possess good film strength or load bearing characteristics; preferably should also be capable of dispersing generated metal fines, that is, not have a tendency to agglomerate metal fines. It should be sufficiently soluble to have a true solubility at F, that is, it should not become pasty or only partially soluble when cooled to about room temperature. The carboxylic acids useful in the invention may be monomeric straight chain monocarboxylic acids, as well as isomers and dimers of such acids. Generally, the carboxylic acids useful in the invention have the formula:

m equals an integer which is at least 1 1, preferably at least 13; not more than 34, and preferably not more than 17;

n is 0 or an even integer from 2 to 6;

r equals 1 or 2.

Examples of higher molecular weight monocarboxylic acids fitting within the above category include oleic acid, linoleic acid, stearic acid, linolenic acid, palmitic acid, myristic acid, and lauric acid, as well as isomers of any of the above acids and dimers thereof. When the dimer is used, preferably the carboxylic acid groups are partially blocked or reacted to provide a stoichiometry less than that of a dicarboxylic acid. preferably approximating that of monocarboxylic acids to avoid the agglomerating tendencies of polycarboxylic acids.

Preferably, the carboxylic acids contains at least 17 carbons in addition to the carboxylic acid group and most preferably the acid comprises oleic acid.

The aliphatic carboxylic acid ester component of the lubricant comprises the esterified product of monocarboxylic acids having at least 4 carbon atoms with mo noalcohols or polyhydroxy alcohols (polyols) including polyhydroxy polyether alcohols. Examples of the monocarboxylic acids which may be used in the ester include butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, and palmitic acid. Examples of such alcohols include methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, propylene glycol, glycerol, diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol. The acids which have been esterified with the alcohol may comprise only one acid or may be a mixture of acids. A commercially available example of a mixture of such acids is Hallco Plasticizer 4141 available from the C. P. Hall Company which comprises a triethylene glycol caprate-caprylate.

The emulsification or dispersion agent used in the lubricant of the invention comprises one or more nonionic and non-metallic emulsifiers which may be an ether or, preferably, an ester. Such emulsifying agents useful in the invention. include polyoxyalkalene oxide ethers or esters of, respectively, C, C alcohols or acids; sorbitan fatty acid esters; and chemical or physical mixtures of such ethers and esters. Examples of such compounds include polyoxyalkalene oxide ethers such as polyoxyethylene lauryl ether; polyoxyalkalene oxide esters such as polyoxyethylene stearate and polyoxyethylene oleate; sorbitan esters such as sorbitan monolaurate, sorbitan mono oleate; or mixed esters such as polyoxyethylene sorbitan mono oleate. In accordance with the invention, physical combinations of such ether and ester emulsifiers may be 'used where there is insufficient stirring or mechanical agitation to maintain the emulsion. For example, it has been found that 4 parts per 100 parts of an ether emulsifier is sufficient where agitation is used such as by stirring or pump recirculation or the like. However, in other instances where, for example, the sheet to be fabricated is lubricated by being merely passed through a pan or trough, it has been found that additional emulsifiers must be used, preferably at least a portion of which are ester based emulsifiers.

The balance of the neat oil comprises mineral oil. The mineral oil is preferably at a viscosity of above 50 SSU to provide sufficient viscosity after dilution with the other ingredients to provide a final viscosity of the neat oil of from 250 to 450 SSU, and preferably from 350 to 400SSU although, as previously mentioned, higher viscosities can be used when operating at higher process equipment temperatures.

It should be recognized that minor amounts of other additives such as corrosion inhibitors, bactericides, or the like may be added where necessary or desired.

The following examples will serve to further illustrate the invention.

EXAMPLE 1 Five parts by weight oleic acid was blended with parts by weight of triethylene glycol caprate caprylate (C. P. Hall Plasticizer 4141), 3 parts by weight polyoxyethylene lauryl ether (Brij 30) and 77 parts by weight ofa mineral oil having a viscosity of about 1,000 SSU (Circo X Heavy). The resulting oil was diluted with water to form a series of emulsions with ratios of 1 part neat oil to 3-9 parts water respectively (in parts by volume). The resulting emulsions had pHs ranging from 5-6. In addition, the neat oil was used as the mechanical oil in the drawing press and the ironing press used to conduct the experiments. A 3004-H19 aluminum alloy metal containing residual rolling lubricants thereon was drawn and ironed to form cans using the above dilutions of lubricant in accordance with the invention. The resulting cans were examined and found to be superior to cans produced under similar conditions using conventional lubricants blended with water. Furthermore, the lubricant was found to actually clean the ironer equipment and exit track work by dispersing the residual metallic debris in the lubricant.

After drawing and ironing the stock, the drawn and ironed cans were washed in water, then in a detergent with a pH controlled to 1.6 with sulfuric acid, followed by subsequent water washings and finally drying. The residual lubricant on the drawn and ironed cans was removed by these washings and recovered by a skimming operation. It was found that the recovered lubricant had not been broken down by the action of the acid. The filters used in the circulation of the lubricant were examined following the drawing operation to deter mine whether any soap formation had occurred resulting in a blinding of the filters used to clean the filter materials. The filter material was found to be in excellent condition without any visible traces of blinding due to soap.

The same results were obtained using the above lubricant on 3004-H19 aluminum alloy with numerous residual oil types and amounts thereon.

EXAMPLE 2 Following the procedures of Example 1, cans were drawn and ironed using a lubricant similar to Example 1 except that lionleic acid, isostearic acid and lauric acid were, respectively, substituted for the oleic acid. Similar results were obtained except that slightly lower lubricant film strength properties resulted.

EXAMPLE 3 To illustrate the use of a combination of emulsifiers, the following neat oil lubricant was formulated:

5 parts oleic acid H5 parts triethylene glycol capratecaprylate (C. P.

Hall Plasticizer 4141) 4 parts polyoxyethylene lauryl ether (Brij 30) 4 parts polyoxyethylene stearate (Mryj 4) 72 parts 1400 SSU Mineral oil A portion of the blended lubricant, which had a viscosity of 4100 SSU, was emulsified using 1 part neat oil per 5 parts deionized water. This portion was used as the metal lubricant in a drawing press. A second portion of the neat oil lubricant was emulsified in a 1:30 neat oil to deionized water ratio and used as the metal lubricant in an ironing press.

In both instances, it was found that the lubricant was sufficiently stable to permit 24-hour (constant) opera tion without replacement of the lubricant because of breakdown. Periodic additions, of course, were made in each instance due to depletion of the lubricant due to spillage and residues on the drawn and ironed can. The lubricant was found to produce cans of superior quality to those produced under similar conditions with conventional lubricants. Furthermore, the dispersion qualities of the lubricant were found to be excellent.

What is claimed is:

1. A metal working lubricant dispersible in an aqueous media comprising:

a. a fatty acid containing at least 12 carbon atoms including at least one carboxylic acid group;

b. an aliphatic carboxylic acid ester;

0. at least one emulsification agent; and

d. mineral oil.

2. The lubricant of claim 1 wherein said carboxylic acid has a formula C l-I (COOH), wherein m is an integer from 11 to 34, n is 0 or an even integer from 2 to 6, and r equals 1 or 2.

3. The lubricant containing the carboxylic acid formula of claim 2 wherein m is an integer from 13 to 17, n is 0 or an even integer from 2 to 4, and r equals 1.

4. The lubricant of claim 1 wherein said aliphatic carboxylic acid ester comprises an esterification product of a glycol selected from the class consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol with one or more aliphatic monocarboxylic acids containing from 6 to 18 carbon atoms.

5. The lubricant of claim 1 wherein the emulsification agent comprises a non-ionic, non-metallic ester or ether of a monocarboxylic acid containing from 12 to 18 carbon atoms.

6. The lubricant of claim 5 wherein said emulsification agent comprises the condensation product of ethylene oxide with an alcohol containing from 12 to 18 carbon atoms. V

7. The lubricant of claim 5 wherein the emulsification agent comprises a mixture of the condensation product of ethylene oxide with a 12 to 18 carbon alcohol and the esterification product of a polyol with one or more 12 to 18 carbon monocarboxylic acids.

8. A metal working lubricant comprising a dispersion of from 10 to 30 parts by weight neat oil and from to parts by weight water, said neat oil comprising in parts by weight.

1. from 2 to 8 parts of a carboxylic acid having the formula C H (COOH wherein m is an integer from 13 to 17, n is 0 or an even integer from 2 to 6 and r is at least 1 and not greater than 2;

2. 10 to 20 parts of an aliphatic carboxylic acid ester comprising the condensation product of one or more 6 18 carbon monocarboxylic acids with a polyol;

3. 2 to 10 parts of at least one emulsification agent selected from the group consisting of esters or ethers of 12 to 18 carbon monocarboxylic acids; and

4. from 60 to 80 parts by weight of a mineral oil having a sufficient initial viscosity to provide a viscosity of the neat oil mixture of from 250 to 450 SSU at F,

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,923,671 DATED December 2 1975 |N\/ ENTOR(S) James E. Knepp It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Col 2 line 56 Change "C H (COOH) to m 2m-n r m 2m-n+2-r (COOH) r Clalm 2 lane 2 Change C H (COOH) r to m 2mn+2-r (COOH) r Clalm 8 line 6 Change C H (COOH) r to a m 2m-n+2-r Q r Signed and Scaled this Twenty-fourth Day Of October 1978 [SEAL] O Attest:

RUTH C. M ASON DONALD W. BANNER Attesm'g m Commissioner of Patents and Trademarks 6 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,923,671 DATED December 2, 1975 INVENTOR(S) James E. Knepp It is certified that error appears in the ab0ve-identitied patent and that said Letters Patent are hereby corrected as shown below:

Col. 3, line 4 Change "acids" to -acid.

Col. 3, line 53 Change "50" to --250-.

Col. 3, line 68 Change "caprate caprylate" to --caprate-caprylate--.

Col. 4, line 52 Change "capratecaprylate" to --caprate-caprylate-. Col. 4, line 55 Change "(Mryj 4)" to --(Mryj 45)-.

C01. 6, line 20 After "6" insert --to-.

Signed and Sealed this sixth Day of April1976 [SEAL] Arrest:

RUTH C. M ASON C. MARSHALL DANN Arresting Officer (mnmissr'oner ofPatenIs and Trademarks 

1. A METAL WORKING LUBRICANT DISPERSIBLE IN AN AQUEOUS MEDIA COMPRISING: A. A FATTY CONTAINING AT LEAST 12 CARBON ATOMS INCLUDINNG AT LEAST ONE CARBOXYLIC ACID GROUP; B. AN ALIPHATIC CARBOXYLIC ACID ESTER; C. AT LEAST ONE EMULSIFICATION AGENT; AND D. MINERAL OIL.
 1. FROM 2 TO 8 PARTS OF A CARBOXYLIC ACID HAVING THE FORMULA CMH2M -N (COOH)R WHEREIN M IS AN INTEGER FROM 13 TO 17, N IS 0 OR AN EVEN INTEGER FROM 2 TO 6 ANDD R IS AT LEAST 1 AND NOT GREATER THAN 2;
 2. 10 TO 20 PARTS OF AN ALIPHATIC CARBOXYLIC ACID ESTER COMPRISING THE CONDENSATION PRODUCT OF ONE OR MORE 6 18 CARBON MONOCARBOXYLIC ACIDS WITH A POLYOL;
 3. 2 TO 10 PARTS OF AT LEAST ONE EMULSIFICATION AGENT SELECTED FROM THE GROUP CONSISTING OF ESTERS OR ETHERS OF 12 TO 18 CARBN MONOCARBOXYLIC ACIDS; AND
 2. The lubricant of claim 1 wherein said carboxylic acid has a formula CmH2m n (COOH)r wherein m is an integer from 11 to 34, n is 0 or an even integer from 2 to 6, and r equals 1 or
 2. 2. 10 to 20 parts of an aliphatic carboxylic acid ester comprising the condensation product of one or more 6 18 carbon monocarboxylic acids with a polyol;
 3. 2 to 10 parts of at least one emulsification agent selected from the group consisting of esters or ethers of 12 to 18 carbon monocarboxylic acids; and
 3. The lubricant containing the carboxylic acid formula of claim 2 wherein m is an integer from 13 to 17, n is 0 or an Even integer from 2 to 4, and r equals
 1. 4. The lubricant of claim 1 wherein said aliphatic carboxylic acid ester comprises an esterification product of a glycol selected from the class consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol with one or more aliphatic monocarboxylic acids containing from 6 to 18 carbon atoms.
 4. FROM 60 TO 80 PARTS BY WEIGHT OF A MINERAL OIL HAVING A SUFFICIENT INITIAL VISCOSITY TO PROVIDE A VISCOSITY OF THE NEAT OIL MIXTURE OF FROM 250 TO 450 SSU AT 100*F.
 4. from 60 to 80 parts by weight of a mineral oil having a sufficient initial viscosity to provide a viscosity of the neat oil mixture of from 250 to 450 SSU at 100*F.
 5. The lubricant of claim 1 wherein the emulsification agent comprises a non-ionic, non-metallic ester or ether of a monocarboxylic acid containing from 12 to 18 carbon atoms.
 6. The lubricant of claim 5 wherein said emulsification agent comprises the condensation product of ethylene oxide with an alcohol containing from 12 to 18 carbon atoms.
 7. The lubricant of claim 5 wherein the emulsification agent comprises a mixture of the condensation product of ethylene oxide with a 12 to 18 carbon alcohol and the esterification product of a polyol with one or more 12 to 18 carbon monocarboxylic acids.
 8. A METAL WORKING LUBRICANT COMPRISING A DISPERSION OF FROM 10 TO 30 PARTS BY WEIGHT NEAT OIL AND FROM 70 TO 90 PARTS BY WEIGHT WATER, SAID NEAT OIL COMPRISING IN PARTS BY WEIGHT. 